1. Field of the Invention
The present invention relates to a method for managing the forwarding of information in a router having a distributed architecture, and more particularly, to a method for dynamically managing the forwarding of information created in a router having a distributed architecture by aggregating or disaggregating forwarding information.
2. Description of the Related Art
Recently, as mass-storage very high speed networks have been developed, router architecture has begun to change from a centralized architecture to a distributed architecture.
A router having a centralized architecture uses a routing protocol in a central processor that is capable of managing routing information collected by the routing protocol. For instance, with a router having a centralized architecture, the central processor calculates routing tables and distributes the routing tables into each line card. Thus, packet forwarding of the line card is carried out based on routing table information transferred from a processor of a central router.
On the contrary, a router having a distributed architecture distributes work to a plurality of processors without concentrating work on the central processor. Thus, a router having a distributed architecture can process relatively greater masses of storage data as compared with a router having a centralized architecture. For example, a router having a distributed architecture includes a first processor for managing the routing protocol, a second processor for calculating the routing table, and a third processor for managing the packet forwarding. That is, work is distributed across the first, second and third processors in an effort to improve routing performance.
A router constructed with a distributed architecture includes a plurality of routing nodes connected to each other through a switching module.
Routing nodes have a routing table for supporting a sub-network and a processor for processing a routing protocol. In addition, each of the routing nodes runs a unique routing protocol and performs a unique forwarding function, even though these routing nodes are regarded as one router in the eyes of a user. These routing nodes are connected to each other through the switching module so as to globally manage routing tables of other routing nodes.
Each input/output processor for each routing mode is divided into a system processor area and a network processor area. The system processor area includes the routing protocols, and a routing table, and the network system processor area includes a forwarding table. The system processor area collects routing information, manages the forwarding table by calculating a route, and enables each input/output processor to share the routing table with the other input/output processors. The network processor forwards work between network devices provided in the local area based on the forwarding table. Thus, a router having distributed architecture can rapidly process masses of stored data.
In order to rapidly process masses of stored data in the distributed architecture of the router, forwarding tables managed by each routing node of the router must be recognized by the other routing nodes within the distributed architecture of the router. A conventional router with distributed architecture transmits forwarding tables between routing nodes through the switching module in such a manner that forwarding tables of routing nodes can be globally managed in each routing node. For example, if the router has ten routing nodes, and each of these ten routing node has ten thousand forwarding entries, then each routing node must manage 100,000 forwarding entries (10×10,000). Accordingly, a conventional router having a distributed architecture requires a large storage capacity in order to store the forwarding tables, thus concomitantly incurring a substantial overhead in required storage capacity.